Abstract Number: Esoc2026a710 Ponticulus Posticus Syndrome Predisposes to Vertebral Artery Dissection and Recurrent Vertebrobasilar Stroke

Abstract Background and aims The atlas normally has a posterior groove for the third segment of the vertebral artery. In some cases, an osseous bridge forms over this groove, creating a bony canal known as arcuate foramen or ponticulus posticus. This structure transmits the vertebral artery and the posterior ramus of the first cervical spinal nerve. Clinically, it has been associated with vertebrobasilar insufficiency, cervicogenic headaches, migraines, and sensorineural hearing disturbances. Methods: Results We report a 58-year-old female with recurrent vertebrobasilar strokes over one year, initially classified as cryptogenic stroke. Chief complaints were dizziness, unsteady gait, left-sided hemiataxia, mild headache. MRI confirmed high-grade stenosis in the left V3 segment. CTA showed a ponticulus posticus adjacent to the stenosis and suggested left vertebral artery dissection with a mural thrombus. Extended anamnestic exploration revealed a prior motor vehicle accident of the patient leading to chronic neck pain treated with osteopathy. We hypothesized that the combination of ponticulus posticus and trauma predisposed to vertebral artery dissection, impaired arterial healing, and recurrent thromboembolic strokes. Treatment involved surgical resection of the bony bridge forming the foramen arcuatum followed by anticoagulation with Dabigatran. Hereby, the stenosis was eliminated, the patient recovered and no further strokes occurred. Conclusions Ponticulus posticus is a common and usually asymptomatic anatomical variant that can pose a risk factor for vertebrobasilar stroke. Cervical trauma in the presence of this bony anomaly can precipitate to vertebral artery dissection. This case underscores the importance of a careful stroke workup in patients with vertebrobasilar stroke. Conflict of interest Blerta Salihaj, Silvia Maria Dumitriu, Frederic Zuhorn, Andreas Rogalewski, Fatemah Sakr, Omid Nikoubashman, Wolf Rüdiger Schäbitz: nothing to disclose Figure 1 - belongs to Background and aims Figure 1 - belongs to Results Figure 1 - belongs to Conclusions